Sciencemadness Discussion Board

Mohr's Titration on Your Soil

aga - 28-12-2015 at 10:41

Today some samphire seeds arrived, and it would be useful to know the NaCl concentration in soil from a coastal area of northern Europe, or any area where the stuff grows naturally.

This study showed that greater than 30g/L NaCl greatly reduces the probability of germination of the seeds, so that would be an upper limit on the concentration desired in the feed water :-

http://digitalcommons.usu.edu/nrei/vol15/iss1/48/

So, if you live near the sea in northern Europe, or have seen some samphire growing near where you live, could you please do a Mohr's Titration to determine the actual chloride content of some soil.

Here's a description of the process :-

http://www.outreach.canterbury.ac.nz/chemistry/chloride_mohr...

Many thanks in advance !

[Edited on 28-12-2015 by aga]

Artemus Gordon - 28-12-2015 at 17:47

Far be it for me to dissuade anyone from doing a Mohr's titration, but I don't quite understand what you are trying to accomplish, Aga. First, in humans, it is generally the Sodium ion that is of concern, not the Chloride. I assume the same thing applies to plants, but I could be wrong. Second, if you are trying to grow samphire (which already is a NaCl tolerant plant) in highly saline soil, wouldn't you be solely concerned with the salinity at your own location? Why would you care about the soil in some other location?
Also, I would think that germination would be more salt-sensitive than growth of a fairly mature plant. If I wanted to grow samphire in maximum saline conditions, I would baby the seeds and then transplant the mature plants to my salty soil.


blogfast25 - 28-12-2015 at 18:25

On the salinity of northern European coastal areas, wide surveys must already exist. Google is your friend.

Even if a few people responded to your call it would only constitute a few, scattered data points.

AG is also right that it's the cations that are important in metabolic electrolytes.

[Edited on 29-12-2015 by blogfast25]

Bert - 28-12-2015 at 20:23


Quote:

Half-way down Hangs one that gathers samphire; dreadful trade! (King Lear- Act IV, Scene VI)


Well, I learned something new today. I knew kelp was gathered to be burned for the residual Soda ash and Iodine compounds, never heard of samphire.

aga - 28-12-2015 at 23:57

The samphire will be grown (if the seeds sprout !) under entirely artifical conditions with no soil and an aqueous feed.

The bible on getting seeds to sprout is "Seed Germination, Theory and Practice" by Norman C Deno - a Chemist ! Well worth looking up if you want to sprout seeds.

Sodium probably is more important as a metabolyte, just that i am familiar with Mohr's method, and measuring the chloride would give a very good indication of the sodium concentration.

Having no samphire locally means that i can't just go take a soil sample to determine exactly how saline the natural conditions are.

A series of 60 day long experiments is obviously possible, just that i hoped somebody was looking for a quick chemistry project, the results being used in a tangible (and protographable) way.